Single gap relay



March 1961 J. c. SCHUESSLER ETAL 2,975,341

SINGLE GAP RELAY Filed June 25, 1958 INVENTORS H 3 JOHN C. SCHUESSLERwwi ATTORNEY United States Patent 0.

SINGLE GAP RELAY John C. Schuessler, West Covina, and Andrew 0. Adams,Inglewood, Califi, assignors to Leach Corporation Filed June 23, 1958,Ser. No. 743,924

8 Claims. or. 317-188 This invention pertains to a relay and moreparticularly to a relay having dual coils and a single working gap.

It is often necessary to provide a relay in a location where excessivebulk or weight cannot be tolerated. This may be, for example, inairplanes or missiles where space and weight always are at a premium. Inmany instances, it may be found that a relay of the conventional singlecoil construction has insufficient holding force for the requirements athand. The problem is made more acute by the fact that the relay in suchinstallations will be subjected to a variety of external forces, such asgravitational and vibrational forces, which add to the force necessaryin moving and holding the armature of the relay. Such forces also haverequired the use of a relatively stiff spring acting on the armature tobias it away from the closed position and prevent inadvertent actuationof the relay. Therefore, the relay coil must overcome considerablespring force when it is energized to close the relay. Also, even thestiffmt springs may resonate with vibrations imposed and allow the relayto close prematurely.

In an effort to alleviate this, it has been proposed to provide a relayhaving two coils operating a single armature. Unfortunately, however,this does not double the holding power of the relay, but results only inthe theoretical maximum of about fifty-nine percent increase inavailable ampere turns. This relatively small increase, despitevirtually doubling the size and weight of the relay results because theprovision of a second coil also adds a second working air gap into thesystem. By far, the greatest loss in relay closing force occurs at theair gap. Heretofore, regardless of the construction or arrangement ofthe armature in the prior art devices, two gaps have been present, :oneat each of the coil cores. These double coil relays also may beadversely affected by gravitational forces.

This invention provides a double coil relay having only a single workinggap. As a result virtually a one hundred percent increase in availableampere turns is obtained. This is accomplished by a unique arrangementof an armature having a large area closely adjacent and pivotingrelative to an enlarged end of the core of one coil so as to move to aposition of contact with the end of the core of the second coil. Theonly working gap present is between the armature and the second core.Furthermore, the armature is counterbalanced, which avoids closing underexternally applied forces and makes unnecessary the use of a stiffspring for loading the armature.

Therefore, it is an object of this invention to provide a single gap,double coil relay having maximum closing force. 7 1

Another object of this invention is to provide a relay which is notadversely affected by vibrational or gravitational forces.

An additional object of this invention is to provide a relay of compactand lightweight construction.

' Yet another object of this invention is to provide a relay having acounterbalanced armature pivoted rela- Patented Mar. 14, 1961 tive toone core end for movement to engage a second core end.

These and other objects will become apparent from the following detaileddescription taken in connection with the accompanying drawing in which:

Fig. l is a top plan view of the relay of this invention,

Fig. 2 is a sectional view taken along line 22 of Fig. 1,

Fig. 3 is a sectional view similar to Fig. 2 of a modified form of theinvention having a unitary armature and offset coils, and

Fig. 4 is a fragmentary sectional view of a further modification inwhich the armature is unitary and includes an offset.

Referring to Figs. 1 and 2 of the drawing, the relay of this inventionincludes coils 1 and 2, which are disposed in an aligned, parallel,side-by-side arrangement. Conventional cores 3 and 4 are within thecoils, but are provided additionally with bottom shoulders 5 and 6 andouter threaded shanks 7 and 8. These shanks of the cores extend throughyoke 9 of magnetic material which abuts one end of each coil, and aresecured thereto by nuts 10 and 11. The yoke, therefore, physicallyconnects the coils and also joins their magnetic circuits.

Aframe 12 of non-magnetic material, such as brass, engages the top endsof the coils and includes a bottom wall 13 receiving cores 3 and 4 whichproject therethrough. Enlarged fiat core heads 14 and 15 are disposedabove bottom wall 13 of the frame. Core head 14 of core 3 is the largerof the two and extends laterally at 16 to a position adjacent to bespaced from square core head 15.

A flat armature 17 is disposed above core head 14 on extension 16thereof and is pivoted with respect thereto. This may be accomplished byproviding a transverse pin 18 interconnecting upwardly extendingparallel sides 19 and 20 of the frame. This pin passes over armature 17and holds the armature adjacent extended portion 16 of core head 14. Asuitable journal arrangement such as member 22 is soldered or otherwiseconnected to arma ture 17 and passes over pin 18. This prevents lateraldisplacement of the armature and maintains the armature in properrelationship with core head 14. Pin 18 and journal 22 hold the armaturevery close to core head 14, but slightly spaced therefrom to allow thearmature to pivot freely about the pin.

In order to permit the pivotal movement of the armature, it is bent asillustrated at location 23 beneath pin 18. Furthermore, the armature isin two sections integrally attached together. Portion 24, which extendsover core head 15, is of magnetic material such as iron. The otherportion extending back over core head 14 is nonmagnetic and may be ofstainless steel. The magnetic portion of the armature includes the bentsection 23, which is enlarged laterally so that a sizable area existsbetween core head 14 and the armature.

Accordingly, when the coils are energized the path of the magnetic fluxis that indicated by the arrows, passing through the cores and the yoketo armature 14 at location 23. The large area at 23 between the armatureand the core means that there is an efficient flux transmissive path atthis point despite the small distance between the armature and core head14. For all practical purposes this minute space-which may be around.002 inch does not exist in the system as far as losses in efiiciencyare concerned. As a result, only one working gap 27, between armatureportion 24 and core head 15, is present in the system. This means thateven though two coils have been provided for the relay, only a singleworking gap is required and virtually a one hundred percent increase inavailable ampere turns is obtained.

The magnetic flux pivots the armature to the position shown in phantomwhere it is in engagement with core end 15. If the armature were notheld a small distance away from core head 14, it would be drawn tightlyagainst this core as well when the coils were energized. This wouldcause sliding between the armature and core 14 when the armature pivotedabout pin 18. Therefore, the frictional force between the armature andcore 14 would prevent the armature from moving smoothly and rapidly toits closed position.

Nonmagnetic portion of the armature serves as a counterbalance so thatthe armature is not affected by gravitational forces. This portion ofthe armature extends back over core 1 and so adds practically noadditional bulk to the unit. By being of nonmagnetic material nomagnetic force tends to draw the armature toward core head 14 when thecoils are energized. With the armature weighing approximately the sameon both sides of the fulcrum, only a light wire spring 28 is required tohold the armature in its normal position away-from core head 15. Thisspring may be wound around pin 18 as illustrated, including one portion29 bearing against the top of portion 25 of the armature while the otherend 30 extends to opening 31 in side 19 of the frame. A slightadditional spring force can be obtained by moving end 3t) upwardly fromopening 31 to opening 31a. Thus, there is no necessity of including astiff spring in the system to engage the armature. No difficulty isencountered from a spring resonating with vibrations in the systembecause the armature is counterbalanced, and practically all of the coilforce is used in moving and holding the armature rather than overcomingspring force.

t is obvious, of course, that the relay in this invention may be used ina variety of ways in the manner of any conventional relay. For example,contactsmay be carried by armature 17 for use in another electricalsystem.

According to the modification of Fig. 3, the armature is a unitarymember, being entirely of magnetic material. This has the advantage ofsimplicity and economy of construction of the armature. However, inorder to avoid a magnetic pull to the second coil, the coils aredisposed in an offset arrangement as illustrated. Thus, as seen in Fig.3, armature 32 is pivotal with respect to projection 33 of core end 34which extends upwardly as well as laterally from the coil end so that arelatively large space 35 exists between counterbalance portion 36 andthis core head. A transverse pin stop 37 prevents armature 32 frompivoting beyond the position illustrated. Of course, bottom wall 40 ofthe frame and yoke 41 also are offset in the construction of this unit.Large gap 35 assures that only negligible magnetic force will be exertedbetween the counterbalance portion of the armature and core end 34.

In the embodiment of Fig. 4, the coils remain in their alignedrelationship, but armature 42 is offset in construction, being of agenerally Z shaped configuration to avoid magnetic pull to core head 14.This results in a wide gap 43 between counterbalance section 44' andcore head 14 so that the armature is not attracted to that core.Transverse pin 45 acts as a stop to prevent further reverse movement ofthe armature, and journal portion 4-6 must be slightly modified in shapefrom the journals used in the previous embodiments.

It is apparent from the foregoing, therefore, that We have provided animproved relay design whereby only a single working gap is present, yettwo coils are included. This relay construction provides twice the forceof single coil relays and much more force than dual coil relays havingtwo gaps. In addition, the armature is fully counterbalanced withoutmaterially adding to the size of the device.

The foregoing detailed description is to be clearly understood as givenby way of illustration and example only, the spirit and scope of thisinvention being limited solely by the appended claims.

We claim:

1. A relay comprising a duality of coils having cores therein andarranged in adjacent relationship, magnetic flux-conductive meansinterconnecting the cores of said coils at one end thereof, an armature,and means mounting said armature in a magnetic flux-conductive workinggap-free relationship on the opposite end of one of said cores so thatsaid armature is pivotal relative to said opposite end between aposition remote from the opposite end of the other of said cores and aposition in contact therewith, whereby only a single working gap isprovided in the magnetic circuit of said relay.

2. A relay comprising a coil assembly including a duality of coils eachhaving a core therein, a yoke interconnecting said cores at one end ofsaid coil assembly for providing a magnetic flux conductor therebetween,a core extension at the opposite end of said coil assembly projectingfrom the first of said cores toward the other, an armature, and meanspivotally mounting said armature with respect to said core extensionwith the pivot point adjacent thereto and said armature in a workinggap-free flux-conductive relationship therewith so that said armatureextends over the second of said cores and is movable relative theretobetween a position remote from said second core and a position inengagement therewith, whereby only a single working gap is provided inthe magnetic flux circuit of said coils.

3. A device as recited in claim 2 in which said armature is providedwith a counterbalance portion projecting from said pivotal mountingmeans away from said second core and in a nonfiux-conductiverelationship with said first core, thereby to balance said armature onsaid core extension.

4. A device as recited in claim 3 in which said coils are axially offsetwith respect to each other whereby said counterbalance portion is remotefrom said first core for all positions of said armature and maintainedin said nonflux-conductive relationship therewith.

5. A relay comprising an assembly of a duality of coils in aside-by-side parallel relationship, a central core element in each ofsaid coils, a yoke of magnetic material interconnecting said coreelements at one end of said coil assembly, the core of the first of saidcoils having a relatively wide extension projecting laterally therefromto a position closely adjacent and spaced from the second of said coresat the opposite end of said coil assembly, and an armature, saidarmature including a portion of magnetic material closely adjacent andpivotal relative to said extension in a working gap-free relationshiptherewith, said portion projecting over said second core and movablebetween a position remote therefrom and a position in engagementtherewith, said armature further including a counterbalance portionprojecting over said first core in a nonfiux-conductive relationshiptherewith.

6. A relay comprising a pair of coils in a side-by-side spaced parallelrelationship, an axially disposed core element in each of said coils, ayoke of magnetic material interconnecting said cores at one end of saidpair of coils, a frame of nonmagnetic material at the opposite end ofsaid pair of coils, said frame having a bottom wall and parallel sidesprojecting therefrom, each of said core elements having a relativelybroad flat portion above said bottom wall, the flat portion for thefirst of said cores being larger than that of the second of said coresand projecting laterally between said sides to a position closelyadjacent and spaced from the fiat portion of the second of said cores,an armature, said armature having a flux-conductive portion of magneticmaterial provided with a relatively large area in juxtaposition and aworking gap-free relationship with said laterally extending portion andpivotal relative thereto, and projecting therefrom over the fiat portionof the second of said core elements for movement between a positionremote therefrom and a position in engagement therewith, said armaturefurther having a counterbalance portion of nonmagnetic materialconnected to said fluxconductive portion and projecting over said flatportion of said first core.

7. A relay comprising a duality of coils in spaced parallelism, anaxially disposed core element in each of said coils, each of said coreelements having a shoulder and a threaded shank projecting therebeyondat one end thereof, a yoke receiving each of said shanks forinterconnecting said cores, said yoke being in engagement with saidshoulders and one end of each of said coils, a nut on each of saidshanks for securing said yoke thereto, a frame at the opposite end ofsaid core elements, said frame having a base wall and two parallel sidewalls projecting from one surface thereof, the opposite surface of saidbase wall engaging the ends of said coils, said core elements extendingthrough said base wall and being provided with enlarged flat headportions engaging said one surface of said base wall, one of said flathead portions being laterally enlarged and extend ing to a positionclosely adjacent and spaced from the other of said head portions, anarmature, said armature having a portion of relatively large area, apivot pin interconnecting said side walls and extending over saidarmature at said portion of relatively large area, said armatureincluding a journal receiving said pin and maintaining said portion ofrelatively large area closely spaced rorn said laterally enlargedportion and pivotal with respect thereto, said armature having twosections the first of which is of magnetic material and includes saidportion of relatively large area and extends therefrom to a positionabove the flat head portion of the other of said core elements formovement upon pivoting of said armature between a position remotetherefrom and a position in engagement therewith, the second section ofsaid armature being of nonmagnetic material and extending from saidportion of relatively large area to a position above the flat headportion of the first of said core elements for countcrbalancing saidarmature, and a relatively light spring member engaging said armatureand biasing said armature to said remote position.

8. A relay comprising a duality of coils having cores therein, magneticflux-conductive means interconnecting the cores of said coils at one endthereof, said cores being provided with flat core heads on the oppositeends thereof, the core head of one of said cores being larger than thecore head of the other and extending laterally toward said core head ofsaid other core, an armature adjacent and in working gap-freeflux-conductive relationship with said larger core head and pivotalrelative to said larger core head between a position remote from thesmaller of said core heads to a position in engagement therewith, and acounterbalance on said armature for balancing the same and precludingmovement thereof in response to externally applied forces.

References Cited in the file of this patent UNITED STATES PATENTS

